1. Field of the Invention
The present invention relates to a compact imaging lens to be mounted in a portable cellular phone or the like, or more particularly, to an imaging lens for imaging an object of broadband light such as white light and a wide angle of view.
2. Description of the Related Art
In recent years, miniaturization of imaging lenses has rapidly progressed along with a transition from photographic film to an image sensor such as a CCD or CMOS, and mounting the imaging lens in a portable cellular phone or the like has come to be achieved. While there is an increasing demand for inexpensiveness due to mass consumption, a technological assignment such as realization of extreme thinness or restrictions specific to electronic light receiving elements has to be satisfied.
Specifically, in recent years, the imaging lens to be mounted in the portable cellular phone or the like has become compact and been requested to offer higher performance of a higher resolution in terms of a resolution or image definition. For satisfying the request, a glass or plastic lens of a two- to four-piece construction has become, as described in patent document 1 (JP-A-2007-298719), patent document 2 (JP-A-2005-326682), and patent document 3 (JP-A-2005-284153), a mainstream of the compact imaging lens to be mounted in the portable cellular phone or the like.